The tops of the side walls of bodies of pickup trucks are commonly provided with rectangular sockets or post pockets primarily intended to receive posts or frame members locating a superstructure such as a truck cap.
Several proposals have been made and devices marketed for removable installation in such sockets so as to provide anchorage for ropes used to tie down a load.
U.S. Pat. No. 3,595,125 issued in July 1971 to Jacobs shows a structure which is expanded into locking engagement with such a socket by rotation of an eyebolt which provides the tie-down. The arrangement is quite simple and effective, but could be loosened by rotation of the eyebolt during use, either inadvertently or as a result of vibration when the tie-down is not in use.
U.S. Pat. No. 4,316,688 issued Feb. 23, 1982 to Roskelley shows a tie-down device which is clearly extremely robust, but which on the other hand is complex both in construction and installation, and could not be rapidly installed and removed as required.
U.S. Design Pat. No. 283,006 shows a molded plastic tie-down bracket which is both cheap to manufacture and very easily and quickly snapped in and out of engagement with a socket. For the same reason that it is easy to remove, it is however directional in its ability to sustain loads, and incorrect installation or roping may easily result in the imposition of forces on the bracket which can disengage it from a socket in which it is engaged. The strength of the bracket is also limited since the load must be sustained by a single upstanding plastic flange through which a rope hole is formed.